Comment 28 for bug 82312

I think the problem is that the current nvidia drivers interact with
x.org in strange and wondrous ways, and work more things out for
themselves than they used to, and take less notice of some bits of
xorg.conf than they used to. So before you give up on Feisty: start
with the stock Feisty nvidia-glx package, back up your present
xorg.conf, then replace the bits you've posted here with this fairly
minimal set:

Section "Device"
 identifier "Default Device"
 driver "nvidia"
EndSection

Section "Monitor"
 identifier "Default Monitor"
 HorizSync 31.0-75.0
 VertRefresh 59
 gamma 0.76
EndSection

Section "Screen"
 Identifier "Default Screen"
 Device "Default Device"
 Monitor "Default Monitor"
 DefaultDepth 24
 Option "Nologo" "true"
 Option "RenderAccel" "true"
 Option "UseEvents" "true"
 Option "ConnectedMonitor" "dfp, crt, tv"
 Option "UseDisplayDevice" "dfp"
 SubSection "Display"
  Depth 24
  Modes "1400x1050" "1280x1024" "1280x960" "1024x768" "800x600"
"640x512" "640x480" "512x384" "400x300" "320x240"
 EndSubSection
EndSection

Section "ServerLayout"
 Identifier "Default Layout"
 Screen "Default Screen" 0 0
 InputDevice "Generic Keyboard"
 InputDevice "Configured Mouse"
EndSection

That should get you up and running with a nice accelerated display on
your flat panel. Once you have that, run the command

nvidia-settings

in a terminal, and mess about with the GUI. You should see all three
display devices (DFP, CRT and TV) represented as boxes in the GUI
under "X Server Display Configuration". The CRT and TV will show as
"disabled" but they will at least be there, and there are a bunch of
options that let you choose what to do with them. Use the GUI to
generate a new x.org config file (don't save it over the existing
one), then edit the new file to put back the Options listed above,
then try backing up the working one and using the new one instead.